*{
    padding: 0;
    margin: 0;
}
#app{
    width: 70%;
    margin: 300px auto;
}
#app:after{
    content: "";
    display: block;
    clear: both;
}
#app ul li{
    width: 11%;
    float: left;
    margin-bottom: 10px;
    list-style: none;
}
#app ul li a{
    text-decoration: none;
    color: #000;
}